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Ask the Diet Doctor: The Truth About MSG

A: Is MSG this horrible thing, as we've been told for so many years, or is it really not bad?

Q: Monosodium glutamate is one of the most avoided food additives in our food supply. It is potentially more polarizing than trans fats. But unlike trans fats, the science behind the MSG doesn’t reveal anything that will cause you to gain weight or drop dead. This may be surprising to you, so let’s look a little at the history of MSG, if there are any health effects you should worry about, and how your can use the flavor-boosting properties of MSG with your own cooking.

MSG BasicsMSG is just a salt molecule combined with the amino acid L-glutamate. The salt molecule is used to stabilize the glutamate molecule, and the amino acid’s glutamate is responsible for umami, the savory fifth flavor. A Japanese scientist initially discovered glutamate’s savory taste properties in 1908 when he decided to figure out what made his wife’s vegetable and tofu soup so delicious. The umami flavor and the use of MSG has long been a staple in Asian cuisine. Food companies like to add MSG to prepared foods, as it makes the food taste like it was made yesterday, despite being make a year ago.

MSG Health ConcernsThe negative health effects of MSG were initially brought into question in a letter published in the New England Journal of Medicine in 1968. In the letter, the authoring physician recounted a negative reaction he had to eating American Chinese food, highlighting MSG as one of the potential causes. This letter lead to a flurry of research surrounding the safety of MSG. Some research that involved injecting mice with high doses of MSG (dosages higher than we could ever aspire to) lead to negative health consequences, but this has never translated to humans most likely because the dose used in the animal studies would be very hard to achieve in a free-living person. In addition, in the animal studies MSG was directly injected to the brain, bypassing all metabolism by the body. Your gut likes to fuel itself on glutamate and a lot of the glutamate you eat never gets past your intestines.

Concerns regarding a link between MSG and obesity have been raised, especially following the publication of a 2011 study in the American Journal of Clinical Nutrition. In this study the researchers followed individuals for an average of 5.5 years to look at the association between obesity and MSG consumption in China (a population that consumes significantly higher levels of MSG then we do in America). The researchers did find that individuals who ate the most MSG (4.2 grams a day) were also the most likely to be overweight compared to individuals who ate the least MSG (0.4g/d). However, people who ate the most MSG were also less active; ate more calories, fat, and carbohydrates; and were more likely to be a smoker. The clumping of these characteristics which we can generally categorize as “unhealthy” makes me bring into question the overall health of the individuals who ate high levels of MSG in this study.

Because that study did show a dose-response relationship between MSG and BMI (more MSG = high BMI), it is important to look at the dose. The intake of the lowest MSG group (0.4 g/d) is right around the average intake of MSG in America. The high intake group ate a daily intake estimated to be consumed by only 2.5 percent of people. Many researchers were critical of this study’s findings. One rebuttal published in the American Journal of Clinical Nutrition concluded, “...extreme caution needs to be exercised not to raise undue public safety concerns regarding MSG consumption.”

In the end, the FDA, World Health Organization, and European Union Food and Agriculture Organization have all vetted the safety of MSG (in moderation of course). While some people can have negative reactions to MSG, these reactions are usually acute. If you are one of these people then you should minimize not just MSG but glutamate-rich umami-packing foods as well (discussed below). For the rest of us, there is no real scientific basis to the fear of MSG.

How to Get Umami Without MSGSo let’s say you want to boost umami flavor in your diet without resorting to sprinkling Accent (the salt-shaker version of MSG) on your steak, what can you do? Here is a list of high-umami foods:

Tomatoes (the riper the tomato, the more umami flavor)

Parmesan cheese

Mushrooms

Soy sauce

Nori

Fish sauce

Chinese cabbage

You might want to limit MSG in your diet primarily because the foods that come with MSG in them are usually of the fast or junk food variety, but while it may sound blasphemous, the strategic use of MSG in your cooking might have the rest of your family thinking you are a better cook than you really are.